Android upload progress

Some time ago I got a task to create a file uploader for Android. Writing file uploader code it not difficult and I’ve done it quickly. To indicate the uploading progress I’ve shown standard rotating progress control while uploading.

But it’s not quite clear for users. Much better is to show the usual progress bar with bytes uploaded and total size. So I decided to implement this user friendliness.

Source code of BackgroundUploader class is here:

class BackgroundUploader extends AsyncTask<Void, Integer, Void> implements DialogInterface.OnCancelListener {

  private ProgressDialog progressDialog;
  private String url;
  private File file;

   public BackgroundUploader(String url, File file) {
    this.url = url;
    this.file = file;
  }

   @Override
  protected void onPreExecute() {
    progressDialog = new ProgressDialog(context);
    progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
    progressDialog.setMessage("Uploading...");
    progressDialog.setCancelable(false);
    progressDialog.setMax((int) file.length());
    progressDialog.show();
  }

   @Override
  protected Void doInBackground(Void... v) {
    HttpURLConnection.setFollowRedirects(false);
    HttpURLConnection connection = null;
    String fileName = file.getName();
    try {
      connection = (HttpURLConnection) new URL(url).openConnection();
      connection.setRequestMethod("POST");
      String boundary = "---------------------------boundary";
      String tail = "\r\n--" + boundary + "--\r\n";
      connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
      connection.setDoOutput(true);

      String metadataPart = "--" + boundary + "\r\n"
          + "Content-Disposition: form-data; name=\"metadata\"\r\n\r\n"
          + "" + "\r\n";

      String fileHeader1 = "--" + boundary + "\r\n"
          + "Content-Disposition: form-data; name=\"uploadfile\"; filename=\""
          + fileName + "\"\r\n"
          + "Content-Type: application/octet-stream\r\n"
          + "Content-Transfer-Encoding: binary\r\n";

       long fileLength = file.length() + tail.length();
      String fileHeader2 = "Content-length: " + fileLength + "\r\n";
      String fileHeader = fileHeader1 + fileHeader2 + "\r\n";
      String stringData = metadataPart + fileHeader;

      long requestLength = stringData.length() + fileLength;
      connection.setRequestProperty("Content-length", "" + requestLength);
      connection.setFixedLengthStreamingMode((int) requestLength);
      connection.connect();

      DataOutputStream out = new DataOutputStream(connection.getOutputStream());
      out.writeBytes(stringData);
      out.flush();

      int progress = 0;
      int bytesRead = 0;
      byte buf[] = new byte[1024];
      BufferedInputStream bufInput = new BufferedInputStream(new FileInputStream(file));
      while ((bytesRead = bufInput.read(buf)) != -1) {
        // write output
        out.write(buf, 0, bytesRead);
        out.flush();
        progress += bytesRead;
        // update progress bar
        publishProgress(progress);
      }

       // Write closing boundary and close stream
      out.writeBytes(tail);
      out.flush();
      out.close();

       // Get server response
      BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
      String line = "";
      StringBuilder builder = new StringBuilder();
      while((line = reader.readLine()) != null) {
        builder.append(line);
      }

    } catch (Exception e) {
      // Exception
    } finally {
      if (connection != null) connection.disconnect();
    }

    return null;
  }

   @Override
  protected void onProgressUpdate(Integer... progress) {
    progressDialog.setProgress((int) (progress[0]));
  }

   @Override
  protected void onPostExecute(Void v) {
    progressDialog.dismiss();
  }

   @Override
  public void onCancel(DialogInterface dialog) {
    cancel(true);
    dialog.dismiss();
  }
}
* This source code was highlighted with Source Code Highlighter.

To execute file uploader the next code should be used:

new BackgroundUploader(url, file).execute();

I wrote the code based on the DNDApplet.java.